Antiperspirant compositions are well known in the personal care art. Ideally antiperspirant compositions are stable compositions that effectively deliver the antiperspirant compound to the skin. In addition, the composition should not leave a visually observable white residue that transfers to the skin or clothing. Deposition of a white residue is esthetically unappealing to the consumer.
Antiperspirant compositions are available in a variety of forms such as aerosol, suspensions, pump, sprays, roll on, powders emulsions, suspensions and solid gels. Antiperspirant compositions additionally have been prepared as either oil in water emulsions or water in oil emulsions. Therefore, antiperspirant compositions of any form typically have a milky or opaque appearance and are manufactured by complex methods. These emulsions contain several types of materials that are insoluble in each other. They include organic oils, silicone compounds, cyclomethicone and water. It is highly desirable to have an additive to place into the composition that will cause all of these various phases that are immicible in each other to form one uniform emulsion, which does not separate. We have surprisingly found a material that contributes this stability and provides outstanding slip to the composition. The inclusion of the compounds into an antiperspirant composition results in an unexpected highly uniform film when applied to the skin. Consequently, a superior heretofore-unattainable antiperspirant results. These properties are highly prized by consumer.
Non-emulsified antiperspirant compositions also are known in the art. However, non-emulsified compositions often require shaking prior to each use in order to re-disperse the insoluble antiperspirant compound that has separated from the compositions. Non-emulsifier antiperspirant compositions that do not require shaking prior to use, are typically pastes or creams that require a high percentage of thickening agents like organo-clay. The presence of organo-clay in the composition is a principal source of the whitening and staining of skin and clothing.
Investigators have searched for antiperspirant compositions that are highly uniform, do not contribute residue to skin or clothes, go on to the skin smoothly and do not separate with time. The inclusion of a specific class of silicone compounds derived from beeswax addresses all of these desired properties.
A roll-on antiperspirant is difficult to formulate and manufacture because the composition requires a sufficient viscosity to adhere to the skin, resist dripping off or running down the skin, and yet is not tacky or sticky. A gel antiperspirant composition is difficult to formulate and manufacture because the composition requires sufficient firmness to withstand rubbing across the skin to deliver a sufficient amount of antiperspirant compound to the skin. Additional formulation parameters include viscosity control lack of syneresis and tackiness.
However, providing a commercially acceptable antiperspirant composition requires overcoming several formulations and manufacturing problems. Antiperspirant compositions, especially in the roll-on or gel form are particularly favored by consumers because such products are esthetically appealing and project the appearance of product purity safety, good performance and being non-whitening. However, due to formulation instability and the difficult manufacture of transparent antiperspirant compositions are not now available to the consumer.
Solid antiperspirant compositions may be divided into three main classes, (a) compressed powder sticks (b) gelled sticks and (c) wax sticks. Each of the three classes has advantages and each also has particular disadvantages. Compressed powder sticks for example, are frequently brittle and hard and leave a cosmetically unacceptable powdery residue after application. Frequently, wax-based products are cosmetically unacceptable because of such factors as hardness, greasiness and tackiness. The opacity of wax sticks and the visually observable white residue that remains after application is also esthetically unacceptable.
Gel type solid antiperspirant compositions have several advantages over both compressed powder sticks and wax sticks. For example, the gel antiperspirant compositions leave fewer residues or dust on the skin. The gel antiperspirant compositions glide more easily over the skin surface resulting in easy and comfortable application of the composition However, preparation of antiperspirant compositions in the form of a stable gel is difficult. For example, a critical ingredient in the gel antiperspirant composition is the gelling agent. Many prior gel antiperspirant compositions comprise hydroalcoholic solutions including a gelling agent such as sodium stearate to form the gel. However, common gelling agent cannot be used in the presence of acidic antiperspirant compounds because of an interaction between the gelling agent which is alkaline and the antiperspirant compound that is acidic.